The Bangkok South Criminal Court on Monday acquitted activist Tantawan "Tawan" Tuatulanon and seven accomplices of lese majeste and sedition charges linked to a 2022 public opinion campaign about royal motorcades.
The court ruled their actions were protected under constitutional rights to freedom of expression.
Prosecutors charged the defendants with violating Sections 112 and 116 of the Criminal Code, along with insulting officials, after they invited the public to place stickers on a whiteboard expressing opinions on royal motorcades.
During proceedings, another defendant, Netiporn "Boong" Saneysangkhom, died in prison, leading the court to dismiss charges against her.
The court said an offence under Section 112 requires actions that directly insult, defame, threaten or demean the monarchy. The judges found the defendants' campaign merely posed a question and did not specifically refer to the King, Queen, heir apparent or regent.
The judges also noted the group did not deliver speeches intended to damage the monarchy's reputation, adding that the three-finger salute displayed by two defendants represented symbolic political expression.
Ruling the actions did not amount to incitement or cause public disorder, the court dismissed the Section 112 and Section 116 charges.
However, the court found the protest violated the 2015 Public Assembly Act because it took place within 150 metres of the Grand Palace without authorisation.
The defendants were convicted of disobeying official orders under Section 368 of the Criminal Code and each fined 5,000 baht.